The aim of the project is to study the biochemical composition of Pigment epithelium, retina, and rod outer segments in normal circumstances and in retinal and choroidal diseases of experimental or genetic origins. Topics of current interest are: (a) study of the concentration and distribution of inorganic constituents by flameless atomic absorption; (b) localization and physiological function of Ca in retina, pigment epithelium and choroid; (c) possible involvement of Ca, Zn and Cu in retinal and choroidal diseases; and (d) study of hybrids of RCS rats and spontaneously hypertensive (SH) rats to determine whether the slow onset type of retinal degeneration seen in the latter is inherited at the rdy or another gene locus or is due to light damage in an albino animal.